#Recommendations for a temp sensor that can handle -10F/-23C?

1 messages · Page 1 of 1 (latest)

loud frigate
#

Looking for a temp (and/or humidity) sensor that can handle low temperatures- the idea here is putting them in my fridge/freezer/deep freeze to track temperatures and create alarms for power outages and such.

Right now I'm using YoLink sensors, which work well enough, but YoLink unfortunately engaged in a bit of light false advertising and isn't actually using LoRa- it's something entirely proprietary that MUST go through their cloud, which is unacceptable for my use case and I'm not spending $300 on their proprietary hub to enable 'local' support. madness.

Zigbee, zwave, or LoRa are all fine. I would prefer to not use bluetooth/wifi. The popular Sonoff sensors are only good to 14F/-10C, which wouldn't work for a deep freeze (which typically sits around 0F/-18C

spice quiver
#

well technically an esp32 and a ds18b20 both have operating temps lower than that level... could probably build something

loud frigate
#

True, but then it's crowding wifi, and using a ton of power

#

would have to constantly replace batteries

spice quiver
#

esp32 can go into deep sleep and only wake on occasion
so you can make it sleep to use minimal power waking up once a minute to check temp and if the temp has changed it powers up the antenna and reports over wifi

#

sure you are still gunna probably have to deal with battery swapping/charging but they can be quite efficient.

#

if your adventurous you could drill a hole for the probe then reseal around it. that way you can have a powered esp outside

loud frigate
#

Honestly that sounds like a lot of work to avoid buying a $20 self contained temperature probe that won't require drilling into my own fridge, will last longer, and will actually do what I want, instead of going over wifi

#

Not sure why you're pushing the esp32 when it's pretty explicitly not what I'm asking for

spice quiver
#

just an easy way of connecting to a ds18b20 is all

#

pretty sure there is one with zigbee too

flint mountain
#

Put it in a freezer set to -23C

#

But if I was serious about putting it there long-term I'd rather probably vacuum seal it though

#

It's the SNZB-02P

flint mountain
#

Also if you want to be extra sure, you could dry it out by putting in a bag with bunch of silica gel for a day or two 🙂

loud frigate
#

Thanks for the information! would get rid of any possibility of humidity reading, of course, but that might be fine.
Would DEFINITELY cause temps to lag though, any idea how badly?

flint mountain
#

No idea, but the sensor took half an hour to go from +20 to -23C, so it's not particularly fast on its own.

flint mountain